I know you can't do this, but I am hoping that someone from Apple sees my suggestion. How about software that recognizes the designated WiFi's such as home and work that you added, and that when you enter and exit those WiFi areas your iPhone locks and unlocks. Having a party at the house or you are skeptic someone may get into your iPhone, there will also be a manual shut down of the software along with security so that no one can turn it back on.